Effects of nature-adapted lighting solutions ("Virtual Sky") on subjective and objective correlates of sleepiness, well-being, visual and cognitive performance at the workplace.

Exposure to natural daylight benefits human well-being, alertness, circadian rhythms and sleep. Many workplaces have limited or no access to daylight. Thus, we implemented a light-panel ("Virtual Sky"), which reproduced nature-adapted light scenarios. In a laboratory office environment, three lighting scenarios were presented during the day: two lighting conditions with nature-adapted spectral light distributions, one with static and one with dynamic clouds, and a standard office lighting condition. We compared the impact of the three lighting scenarios on subjective and objective measures of alertness, cognitive performance, wellbeing, visual comfort, contrast sensitivity, and cortisol levels in 18 healthy young male volunteers in a within-participant cross-over study design. We found no evidence that an 8-h lighting scenario with static or dynamic clouds during the waking day (9am-5pm) was associated with any significant effect on objective and/or subjective alertness, cognitive performance and morning cortisol concentrations compared to standard workplace lighting. However, the dynamic light scenario was accompanied with lower levels of perceived tensionafter completing cognitive tasks and less effort to concentrate compared to the static lighting scenarios. Our findings suggest that apart from smaller effects on tension and concentration effort, nature-adapted lighting conditions did not improve daytime alertness and cognitive performance in healthy well-rested young participants, as compared to standard office lighting.

Encoding of everyday objects in older adults: Episodic memory assessment in virtual reality.

Introduction: Age-related decline in episodic memory performance in otherwise healthy older adults is indisputably evident. Yet, it has been shown that under certain conditions episodic memory performance in healthy older adults' barely deviates from those seen in young adults. Here we report on the quality of object encoding in an ecologically valid, virtual-reality based memory assessment in a sample of healthy older and younger adults with comparable memory performance. Methods: We analyzed encoding by establishing both a serial and semantic clustering index and an object memory association network. Results: As expected, semantic clustering was superior in older adults without need for additional allocation of executive resources whereas young adults tended more to rely on serial strategies. The association networks suggested a plethora of obvious but also less obvious memory organization principles, some of which indicated converging approaches between the groups as suggested by a subgraph analysis and some of which indicated diverging approaches as suggested by the respective network interconnectivity. A higher interconnectivity was observed in the older adults' association networks. Discussion: We interpreted this as a consequence of superior semantic memory organization (extent to which effective semantic strategies diverged within the group). In conclusion, these results might indicate a diminished need for compensatory cognitive effort in healthy older adults when encoding and recalling everyday objects under ecologically valid conditions. Due to an enhanced and multimodal encoding model, superior crystallized abilities might be sufficient to counteract an age-related decline in various other and specific cognitive domains. This approach might potentially elucidate age-related changes in memory performance in both healthy and pathological aging.

Digitally Assisted Standard Diagnostics in Insurance Medicine (DASDIM): psychometric data in psychiatric work disability evaluations.

PURPOSE: Insurers often commission psychiatric experts to evaluate the eligibility of workers with mental disorders for disability benefits, by estimating their residual work capacity (RWC). We investigated the validity of a standardized, computer-based battery of established diagnostic instruments, for evaluating the personality, cognition, performance, symptom burden, and symptom validity of claimants. METHODS: One hundred and fifty-three claimants for benefits were assessed by the assembled test battery, which was applied in addition to a conventional clinical work disability evaluation. RESULTS: A principal component analysis of the test and questionnaire battery data revealed six factors (Negative Affectivity, Self-Perceived Work Ability, Behavioral Dysfunction, Working Memory, Cognitive Processing Speed, and Excessive Work Commitment). Claimants with low, medium, and high RWC exclusively varied in the factor Negative Affectivity. Importantly, this factor also showed a strong association to psychiatric ratings of capacity limitations in psychosocial functioning. CONCLUSIONS: The findings demonstrate that the used test battery allows a substantiation of RWC estimates and of psychiatric ratings by objective and standardized data. If routinely incorporated in work disability evaluations, the test battery could increase their transparency for all stakeholders (insurers, claimants, medical experts, expert case-coordinators, and legal practitioners) and would open new avenues for research in the field of insurance medicine.Implications for rehabilitationThe residual work capacity (RWC) estimation by medical experts is internationally good practice, but plagued by a relatively low interrater agreement.The current study shows that psychiatric RWC estimates and capacity limitation ratings can be substantiated by data from objective, standardized psychometric instruments.Systematically using such instruments might help to improve the poor interrater agreement for RWC estimates in work disability evaluations.Such data could also be used for adopting vocational trainings and return-to-work programs to the individual needs of workers with mental health problems.

No evidence for auditory N1 dishabituation in healthy adults after presentation of rare novel distractors.

Previous studies were not able to show that presentation of change stimuli leads to dishabituation of the auditory evoked potential (AEP) component N1 for repeated stimuli. However, these change stimuli were usually themselves repeatedly presented. Here, we tested whether the presentation of non-repeating distractor stimuli ('novels') would lead to N1 dishabituation. The study sample consisted of 18 healthy participants who had to identify auditory target stimuli (´targets´) among repeated standard stimuli and rare novels. AEPs to standards were separately averaged, depending on the preceding stimulus (standards after standards, standards after targets, and standards after novels) and were compared by F statistics and Bayesian t-test. Moreover, N1 repetition effects within recording blocks were analyzed in single trial analyses. The analyses showed that targets elicited significantly larger N1 amplitudes than standards and standards elicited larger N1 amplitudes than novels. In contrast, the N1 amplitude to standards did not vary with the preceding stimulus. The single trial analyses revealed significant, but similar N1 amplitude decreases within the recording blocks for all standards. The current study revealed no evidence for N1 dishabituation, as the N1 amplitude for standards after novels was not increased as compared to the N1 for standards after standards. Thus, stimulus variation had no impact on the N1 of repeated standards, as also suggested by the single trial analyses. The lack of N1 dishabituation is at odds with the assumption that the N1 amplitude decrease after repeated stimulation results from habituation.

The reduced auditory evoked potential component N1 after repeated stimulation: Refractoriness hypothesis vs. habituation account.

Similar to other event-related potential (ERP) components, the amplitude of the auditory evoked N1 depends on the interstimulus interval (ISI). At ISIs > 0.4 s, the amplitude of the N1 increases with longer ISIs, until it saturates at ISIs around 10 s. This amplitude increase with increasing ISI has been conceptualized as a function of N1 recovery or N1 refractoriness. Habituation (as a simple form of learning) represents an elaborated, opposing account for such stimulus repetition effects. For passive oddball experiments (stimulation protocols with frequent standards and rare deviants), the two accounts make different predictions. According to the habituation account, the presentation of small deviants should lead to an increased N1 for subsequent standards (= dishabituation); according to the N1 refractoriness account, there should be no or just minor effects on the N1. In the current study, we tested these predictions and compared the ERPs to standards after small deviants and to standards preceded by other standards. We observed that the ERPs to standards after small deviants were characterized by a small mismatch negativity with an onset latency > 150 ms, but the N1 to standards after deviants did not differ from the N1 to standards preceded by other standards. This negative finding is in line with other previous studies that were also not able to reveal evidence for N1 dishabituation. Aside from this repeated lack of evidence for dishabituation, the N1 habituation account is challenged by the finding that the N1 decrease is stronger for more intense stimuli. Overall, the current and previous findings are more compatible with the N1 refractoriness account, although the mechanisms underlying N1 refractoriness remain to be elucidated. Knowledge about these mechanisms would also help to understand why N1 deficits in schizophrenia are more pronounced at longer ISIs.

The reproducibility of psychiatric evaluations of work disability: two reliability and agreement studies.

BACKGROUND: Expert psychiatrists conducting work disability evaluations often disagree on work capacity (WC) when assessing the same patient. More structured and standardised evaluations focusing on function could improve agreement. The RELY studies aimed to establish the inter-rater reproducibility (reliability and agreement) of 'functional evaluations' in patients with mental disorders applying for disability benefits and to compare the effect of limited versus intensive expert training on reproducibility. METHODS: We performed two multi-centre reproducibility studies on standardised functional WC evaluation (RELY 1 and 2). Trained psychiatrists interviewed 30 and 40 patients respectively and determined WC using the Instrument for Functional Assessment in Psychiatry (IFAP). Three psychiatrists per patient estimated WC from videotaped evaluations. We analysed reliability (intraclass correlation coefficients [ICC]) and agreement ('standard error of measurement' [SEM] and proportions of comparisons within prespecified limits) between expert evaluations of WC. Our primary outcome was WC in alternative work (WCalternative.work), 100-0%. Secondary outcomes were WC in last job (WClast.job), 100-0%; patients' perceived fairness of the evaluation, 10-0, higher is better; usefulness to psychiatrists. RESULTS: Inter-rater reliability for WCalternative.work was fair in RELY 1 (ICC 0.43; 95%CI 0.22-0.60) and RELY 2 (ICC 0.44; 0.25-0.59). Agreement was low in both studies, the 'standard error of measurement' for WCalternative.work was 24.6 percentage points (20.9-28.4) and 19.4 (16.9-22.0) respectively. Using a 'maximum acceptable difference' of 25 percentage points WCalternative.work between two experts, 61.6% of comparisons in RELY 1, and 73.6% of comparisons in RELY 2 fell within these limits. Post-hoc secondary analysis for RELY 2 versus RELY 1 showed a significant change in SEMalternative.work (- 5.2 percentage points WCalternative.work [95%CI - 9.7 to - 0.6]), and in the proportions on the differences ≤ 25 percentage points WCalternative.work between two experts (p = 0.008). Patients perceived the functional evaluation as fair (RELY 1: mean 8.0; RELY 2: 9.4), psychiatrists as useful. CONCLUSIONS: Evidence from non-randomised studies suggests that intensive training in functional evaluation may increase agreement on WC between experts, but fell short to reach stakeholders' expectations. It did not alter reliability. Isolated efforts in training psychiatrists may not suffice to reach the expected level of agreement. A societal discussion about achievable goals and readiness to consider procedural changes in WC evaluations may deserve considerations.

Inhibition and attentional control in pedophilic child sexual offenders - An event-related potential study.

OBJECTIVE: Impaired response inhibition might play a role in child sexual offences. Recording of event-related potentials (ERPs) can help to clarify whether child sexual offenders (CSOs) show an altered processing of stop signals and commission errors. METHODS: In the current ERP study, we investigated these processes in a Go/Nogo task on two groups of CSOs, pedophilic contact CSOs and non-contact CSOs (child pornography offenders), as well as on non-offenders as controls. RESULTS: Behaviorally, CSOs showed a slight, but non-significant increase of the false alarm rate to Nogo cues, as compared to controls. The amplitudes of the ERP components N2 and P3 to Nogo cues followed by correctly withhold responses did not vary between CSOs and controls. The analysis of the ERPs to committed errors showed that the Ne amplitudes (reflecting error detection) did not differ between the groups either, whereas the Pe amplitudes (reflecting error evaluation and error awareness) were strongly diminished in CSOs. This diminishment was primarily found in contact CSOs. CONCLUSIONS: The findings suggest that response inhibition, processing of stop signals, and error detection are not necessarily impaired in CSOs. However, CSOs appear to dedicate less cognitive resources to the evaluation of committed errors. SIGNIFICANCE: This selective alteration could reflect a reduced sense of responsibility for misconduct in this offender group, which might contribute to their delinquent behavior.

The event-related potential component P3a is diminished by identical deviance repetition, but not by non-identical repetitions.

Mismatch negativity (MMN) represents an event-related potential (ERP) component which is elicited by deviant sound events in an otherwise regular, repetitive stimulation. The MMN amplitude typically decreases when two identical deviants are presented in direct succession, but it remains stable when the two deviants vary from the standard in different features. Less is known about such repetition effects on another ERP component, the P3a, which usually follows the MMN. In the current study, we investigated how the P3a was affected by identical and non-identical repetitions of sound deviants. The ERP analysis revealed that the P3a amplitudes were strongly diminished when the repeated deviants were identical, but the P3a remained stable when the repeated deviants varied. The findings suggest that not only the deviance detection system, as reflected in the MMN, but also subsequent attention switch systems, as reflected in the P3a, operate independently across different sound features.

Resting-state functional connectivity remains unaffected by preceding exposure to aversive visual stimuli.

While much is known about immediate brain activity changes induced by the confrontation with emotional stimuli, the subsequent temporal unfolding of emotions has yet to be explored. To investigate whether exposure to emotionally aversive pictures affects subsequent resting-state networks differently from exposure to neutral pictures, a resting-state fMRI study implementing a two-group repeated-measures design in healthy young adults (N = 34) was conducted. We focused on investigating (i) patterns of amygdala whole-brain and hippocampus connectivity in both a seed-to-voxel and seed-to-seed approach, (ii) whole-brain resting-state networks with an independent component analysis coupled with dual regression, and (iii) the amygdala's fractional amplitude of low frequency fluctuations, all while EEG recording potential fluctuations in vigilance. In spite of the successful emotion induction, as demonstrated by stimuli rating and a memory-facilitating effect of negative emotionality, none of the resting-state measures was differentially affected by picture valence. In conclusion, resting-state networks connectivity as well as the amygdala's low frequency oscillations appear to be unaffected by preceding exposure to widely used emotionally aversive visual stimuli in healthy young adults.

[Symptom Validation in Independent Medical Evaluations]. / Beschwerdenvalidierung in der versicherungsmedizinischen Begutachtung.

High prevalence rates of non-authentic complaints identified by experts in the field of insurance medicine draw attention to the risk of services, which are of limited availability and financially compensated, being used in ways that are not goal-oriented. Therefore, symptom validity testing has become a growing issue to prevent non-targeted monetary compensations. This paper outlines the best-evaluated methods and instruments. Based on the data currently available, their validity, in particular in the context of medico-legal assessment, is assessed. It is concluded that symptom validity assessment allows inferences about the degree of certainty of clinical judgements on the authenticity of reported symptoms. Thus, the application of the suggested instruments enhances significantly the quality of medical and psychological expertise. However, the integration of the additional results into the overall assessment is challenging and needs to be further clarified.

Use of a structured functional evaluation process for independent medical evaluations of claimants presenting with disabling mental illness: rationale and design for a multi-center reliability study.

BACKGROUND: Work capacity evaluations by independent medical experts are widely used to inform insurers whether injured or ill workers are capable of engaging in competitive employment. In many countries, evaluation processes lack a clearly structured approach, standardized instruments, and an explicit focus on claimants' functional abilities. Evaluation of subjective complaints, such as mental illness, present additional challenges in the determination of work capacity. We have therefore developed a process for functional evaluation of claimants with mental disorders which complements usual psychiatric evaluation. Here we report the design of a study to measure the reliability of our approach in determining work capacity among patients with mental illness applying for disability benefits. METHODS/DESIGN: We will conduct a multi-center reliability study, in which 20 psychiatrists trained in our functional evaluation process will assess 30 claimants presenting with mental illness for eligibility to receive disability benefits [Reliability of Functional Evaluation in Psychiatry, RELY-study]. The functional evaluation process entails a five-step structured interview and a reporting instrument (Instrument of Functional Assessment in Psychiatry [IFAP]) to document the severity of work-related functional limitations. We will videotape all evaluations which will be viewed by three psychiatrists who will independently rate claimants' functional limitations. Our primary outcome measure is the evaluation of claimant's work capacity as a percentage (0 to 100 %), and our secondary outcomes are the 12 mental functions and 13 functional capacities assessed by the IFAP-instrument. Inter-rater reliability of four psychiatric experts will be explored using multilevel models to estimate the intraclass correlation coefficient (ICC). Additional analyses include subgroups according to mental disorder, the typicality of claimants, and claimant perceived fairness of the assessment process. DISCUSSION: We hypothesize that a structured functional approach will show moderate reliability (ICC ≥ 0.6) of psychiatric evaluation of work capacity. Enrollment of actual claimants with mental disorders referred for evaluation by disability/accident insurers will increase the external validity of our findings. Finding moderate levels of reliability, we will continue with a randomized trial to test the reliability of a structured functional approach versus evaluation-as-usual.

Functional Somatic Syndromes: Skin Temperatures and Activity Measurements Under Ambulatory Conditions.

Functional somatic syndromes are mostly associated with pain and emotional distress. As one marker for the autonomic stress response, the distal skin temperature decreases during psychological stress. In patients with functional somatic syndromes, the distal skin temperature under baseline conditions (without stress induction) is usually lower than in healthy subjects, which could be due to the sustained presence of pain-related stress in such patients. The aim of our study was to investigate whether patients with functional somatic syndromes show altered skin temperatures also under everyday life conditions. 14 patients with functional somatic syndromes and 14 matched healthy control subjects were investigated under ambulatory conditions over six consecutive days. During this time, distal and proximal skin temperatures were continuously recorded and sleep-wake cycles were monitored by actimetry and sleep-wake diaries. Unexpectedly, the patients showed higher distal skin temperatures than control subjects in the afternoon. The objective temperature data did not match the patients' subjective experience: ratings of thermal comfort did not vary between the two groups. Moreover, similar levels of daytime activity were recorded in the two samples, even though patients reported more tiredness and more body tension than controls. We interpret the observed dissociation between objective skin temperature measurements and subjective ratings of the bodily thermal comfort as support for the notion of an alexisomia account (reduced bodily awareness) for functional somatic syndromes. Moreover, findings indicate that subjective complaints of tiredness and tension do not necessarily result in physical avoidance behaviour.

Attitudes towards evaluation of psychiatric disability claims: a survey of Swiss stakeholders.

QUESTIONS: In Switzerland, evaluation of work capacity in individuals with mental disorders has come under criticism. We surveyed stakeholders about their concerns and expectations of the current claim process. METHODS: We conducted a nationwide online survey among five stakeholder groups. We asked 37 questions addressing the claim process and the evaluation of work capacity, the maximum acceptable disagreement in judgments on work capacity, and its documentation. RESULTS: Response rate among 704 stakeholders (95 plaintiff lawyers, 285 treating psychiatrists, 129 expert psychiatrists evaluating work capacity, 64 social judges, 131 insurers) varied between 71% and 29%. Of the lawyers, 92% were dissatisfied with the current claim process, as were psychiatrists (73%) and experts (64%), whereas the majority of judges (72%) and insurers (81%) were satisfied. Stakeholders agreed in their concerns, such as the lack of a transparent relationship between the experts' findings and their conclusions regarding work capacity, medical evaluations inappropriately addressing legal issues, and the experts' delay in finalising the report. Findings mirror the characteristics that stakeholders consider important for an optimal work capacity evaluation. For a scenario where two experts evaluate the same claimant, stakeholders considered an inter-rater difference of 10%‒20% in work capacity at maximum acceptable. CONCLUSIONS: Plaintiff lawyers, treating psychiatrists and experts perceive major problems in work capacity evaluation of psychiatric claims whereas judges and insurers see the process more positively. Efforts to improve the process should include clarifying the basis on which judgments are made, restricting judgments to areas of expertise, and ensuring prompt submission of evaluations.

Evaluation of work capacity in Switzerland: a survey among psychiatrists about practice and problems.

QUESTIONS UNDER STUDY: In Switzerland, psychiatric evaluations of work capacity for determining a person's eligibility for disability benefits are being criticised for a lack of transparency and high inter-rater variability. The aims of this study were to learn about the current practice of psychiatrists, to explore possible sources for lack of transparency and variability, and to contrast practice with current professional guidance. METHODS: A national online-survey among psychiatrists who performed five or more evaluations of work capacity per year. Based on discussions with experts and a literature review, we structured questions focusing on reporting on work capacity, the description of a claimant's previous job, and measures of quality assurance. RESULTS: A total of 129 psychiatrists responded (31% of estimated 412 eligible psychiatrists). The majority reported using instructions of the insurers (77%), peer consulting (65%) and process guidelines (51%). They expressed a claimant's work capacity as free text and percentage work capacity (49%), percentage only (23%), or free text only (14%). A total of 13% used instruments to document work capacity. Psychiatrists considered three different interpretations of percentage work capacity as equally applicable. A job description was regarded as mandatory to determine work capacity by 90% but only 26% received it and found it mostly deficient. CONCLUSIONS: The transparency and reliability of Swiss psychiatrists' conclusions on a claimant's work capacity may be reduced by unsystematic reporting, variable interpretation of the percentage work capacity, lack of a detailed job description and insufficient quality control. Education, engagement of insurers and new guidelines might be effective means of implementing improvements.

Response inhibition in pedophilia: an FMRI pilot study.

BACKGROUND: The failure to inhibit pleasurable but inappropriate urges is associated with frontal lobe pathology and has been suggested as a possible cause of pedophilic behavior. However, imaging and neuropsychological findings about frontal pathology in pedophilia are heterogeneous. In our study we therefore address inhibition behaviorally and by means of functional imaging, aiming to assess how inhibition in pedophilia is related to a differential recruitment of frontal brain areas. METHOD: Eleven pedophilic subjects and 7 nonpedophilic controls underwent fMRI while performing a go/no-go task composed of neutral letters. RESULTS: Pedophilic subjects showed a slower reaction time and less accurate visual target discrimination. fMRI voxel-level ANOVA revealed as a main effect of the go/no-go task an activation of prefrontal and parietal brain regions in the no-go condition, while the left anterior cingulate, precuneus and gyrus angularis became more activated in the go condition. In addition, a group × task interaction was found in the left precuneus and gyrus angularis. This interaction was based on an attenuated deactivation of these brain regions in the pedophilic group during performance of the no-go condition. The positive correlation between blood oxygen level-dependent imaging signal and reaction time in these brain areas indicates that attenuated deactivation is related to the behavioral findings. CONCLUSION: Slower reaction time and less accurate visual target discrimination in pedophilia was accompanied by attenuated deactivation of brain areas belonging to the default mode network. Our findings thus support the notion that behavioral differences might also derive from self-related processes and not necessarily from frontal lobe pathology.

Immediate processing of erotic stimuli in paedophilia and controls: a case control study.

BACKGROUND: Most neuroimaging studies investigating sexual arousal in paedophilia used erotic pictures together with a blocked fMRI design and long stimulus presentation time. While this approach allows the detection of sexual arousal, it does not enable the assessment of the immediate processing of erotically salient stimuli. Our study aimed to identify neuronal networks related to the immediate processing of erotic stimuli in heterosexual male paedophiles and healthy age-matched controls. METHODS: We presented erotic pictures of prepubescent children and adults in an event related fMRI-design to eight paedophilic subjects and age-matched controls. RESULTS: Erotic pictures of females elicited more activation in the right temporal lobe, the right parietal lobe and both occipital lobes and erotic pictures of children activated the right dorsomedial prefrontal cortex in both groups. An interaction of sex, age and group was present in the right anteriolateral oribitofrontal cortex. CONCLUSIONS: Our event related study design confirmed that erotic pictures activate some of the brain regions already known to be involved in the processing of erotic pictures when these are presented in blocks. In addition, it revealed that erotic pictures of prepubescent children activate brain regions critical for choosing response strategies in both groups, and that erotically salient stimuli selectively activate a brain region in paedophilic subjects that had previously been attributed to reward and punishment, and that had been shown to be implicated in the suppression of erotic response and deception.

Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance.

Many people spend an increasing amount of time in front of computer screens equipped with light-emitting diodes (LED) with a short wavelength (blue range). Thus we investigated the repercussions on melatonin (a marker of the circadian clock), alertness, and cognitive performance levels in 13 young male volunteers under controlled laboratory conditions in a balanced crossover design. A 5-h evening exposure to a white LED-backlit screen with more than twice as much 464 nm light emission {irradiance of 0,241 Watt/(steradian × m(2)) [W/(sr × m(2))], 2.1 × 10(13) photons/(cm(2) × s), in the wavelength range of 454 and 474 nm} than a white non-LED-backlit screen [irradiance of 0,099 W/(sr × m(2)), 0.7 × 10(13) photons/(cm(2) × s), in the wavelength range of 454 and 474 nm] elicited a significant suppression of the evening rise in endogenous melatonin and subjective as well as objective sleepiness, as indexed by a reduced incidence of slow eye movements and EEG low-frequency activity (1-7 Hz) in frontal brain regions. Concomitantly, sustained attention, as determined by the GO/NOGO task; working memory/attention, as assessed by "explicit timing"; and declarative memory performance in a word-learning paradigm were significantly enhanced in the LED-backlit screen compared with the non-LED condition. Screen quality and visual comfort were rated the same in both screen conditions, whereas the non-LED screen tended to be considered brighter. Our data indicate that the spectral profile of light emitted by computer screens impacts on circadian physiology, alertness, and cognitive performance levels. The challenge will be to design a computer screen with a spectral profile that can be individually programmed to add timed, essential light information to the circadian system in humans.

Mismatch and conflict: neurophysiological and behavioral evidence for conflict priming.

Conflict-related cognitive processes are critical for adapting to sudden environmental changes that confront the individual with inconsistent or ambiguous information. Thus, these processes play a crucial role to cope with daily life. Generally, conflicts tend to accumulate especially in complex and threatening situations. Therefore, the question arises how conflict-related cognitive processes are modulated by the close succession of conflicts. In the present study, we investigated the effect of interactions between different types of conflict on performance as well as on electrophysiological parameters. A task-irrelevant auditory stimulus and a task-relevant visual stimulus were presented successively. The auditory stimulus consisted of a standard or deviant tone, followed by a congruent or incongruent Stroop stimulus. After standard prestimuli, performance deteriorated for incongruent compared to congruent Stroop stimuli, which were accompanied by a widespread negativity for incongruent versus congruent stimuli in the event-related potentials (ERPs). However, after deviant prestimuli, performance was better for incongruent than for congruent Stroop stimuli and an additional early negativity in the ERP emerged with a fronto-central maximum. Our data show that deviant auditory prestimuli facilitate specifically the processing of stimulus-related conflict, providing evidence for a conflict-priming effect.

[Lithium intoxications at normal serum levels]. / Schwere lithiumintoxikationen bei normalen serumspiegeln.

OBJECTIVE: Lithium is known to be neurotoxic at higher serum levels. In rare cases patients develop symptoms of intoxication or full blown intoxications even when lithium levels are normal. Our aim was to detect predicting factors of lithium neurotoxicity at normal serum lithium levels in order to allow prevention of those constellations. METHODS: We report two cases of severe lithium intoxications at normal serum lithium levels and review the current literature concerning lithium neurotoxicity at normal serum levels. RESULTS: It appears that the probability of developing signs of lithium intoxications in patients treated with lithium is increased with advanced age, co-morbidity with pre-existing neurological or other general diseases, especially those associated with fever, and in combination with the use of antipsychotics, antidepressants or mood stabilizers. The serum lithium level does not necessarily detect an intoxication. CONCLUSIONS: In patients developing signs of intoxication under lithium therapy, further investigations should include serum levels and an EEG. Because intoxications can occur even in normal serum levels, discontinuation of lithium medication should be taken into account on the basis of clinical signs of intoxication.